Summary

A professor tells the group about a hidden Spirit Library in the desert. Inside, Sokka discovers a crucial weakness of the Fire Nation that could end the war: the date of the upcoming solar eclipse. However, the spirit of the library, Wan Shi Tong, begins to sink the library, thinking that Sokka will only use the knowledge to fuel a war. Outside, Toph is distracted by the library sinking, and cannot defend Appa while he is kidnapped by Sandbenders. They all escape from the library but are devastated by Appa's disappearance.